Hb A1c

1. 1
Diagnostic criteria
for impair glucose metabolism

2. 2
Diagnostic criteria for impair glucose metabolism
Criteria ADA WHO
Normoglycemia FPG<100 mg/dl FPG<110 mg/dl
2h PG<140 mg/dl 2 hPG<140 mg/dl
IFG FPG≥100 and <126 mg/dl FPG≥110 and <126 mg/dl
IGT 2h PG≥140 and <200 mg/dl 2h PG≥140 and <200 mg/dl
Diabetes FPG≥126 mg/dl FPG≥126 mg/dl
2h PG≥200 mg/dl 2h PG≥200 mg/dl
Symtoms of DM and casual
PG≥200 mg/dl
Note: To convert from the conventional unit to SI unit multiply by 0.0555

3. 3
Risk factors for type II DM
• Age ≥ 45 years
• Over weight (BMI > 25 kg/m
2
)
• Family history of DM
• Physical inactivity
• Previously identify IFG or IGT
• History of GDM or delivery of a baby weight > 4 kg
• Hypertension
• HDL-Cholesterol ≤ 35 mg/dl (0.90 mmol/l)
and/or TG ≥ 250 mg/dl (2.82 mmol/l)
• PCOS
• History of vascular disease: CAD, ischemic stroke

4. 4
Impaired fasting glucose and impaired glucose tolerance
Form an intermediate stage in the natural history of DM
Incidence: 10-15 % of population
The first glucose abnormality is a rise in the postprandial
glucose (IGT). With time, further decline in beta-cell
function leads to IFG
Postprandial glucose has higher sensitivity for predicting
progression to DM than IFG and more strongly
associated with CVD outcome

5. 5
Hemoglobin A1c
A subset of glycated Hb, accumulate in RBC in
proportion to blood glucose level
Provide an overall measure of a patient’s plasma glucose
during the previous 2-3 months
Represents the effect of fasting and postprandial
glucose level
It is the gold standard for assessing glycemic control in
patients with DM since it is an important marker
for micro and macrovascular complication

6. 6
Correlation between mean blood glucose and HbA1c
There is a linear relationship between HbA1c and
mean plasma glucose (MPG)
HbA1c (%) MPG (mg/dl)
6 120
7 150
8 180
9 210
10 240
11 270
Formular: MPG= (33.3 x HbA1c)-86

7. 7
Glycemic goal for adult with DM
Glycemic parameter ACE ADA
HbA1c ≤ 6.5% < 7%
FPG < 110 mg/dl 90-130 mg/dl
postprandial glucose < 140 mg/dl < 180
In non-diabetes, increase HbA1c is associated with a significant
increase risk of cardiovascular and cerebrovascular disease with
hazard ratio of 1.13-1.7 at HbA1c ≥ 5.7%

8. 8
Application of IFG and HbA1c for diagnosis of IGT/DM
NIH study estimate the rate of progression from IFG to DM in:
• New IFG criteria (100-109 mg/dl)= 1.34%/yr
• Old IFG criteria (110-125 mg/dl)= 5.56%/yr
Predictor of hyperglycemia progression
younger age
Female
high BMI
low HDL and high TG
high systolic BP
• A combination of FPG ≥ 102 mg/dl and HbA1c ≥ 5.7 is highly
predictive of IGT (Sensitivity, specificity 85%)
• HbA1c ≥ 7% : Sensitivity > 90% for DM

9. 9
HgbA1c
• 505 subjects screened for type 2 diabetes
• Only 4 %identified by fasting blood
glucose as opposed to 10.4% by OGTT
• HgbA1c >= 6.2% had 100% correlation with
OGTT diagnosis
• Cardiovascular risk in increased 1.8-2.2 times at HgbA1c
of 5.6-6.1%; increased 2 times at >= 6.2%
Diabetes Care 2003,26(2): 485-90
AIMA-VI (Dr.Richard Brown,
Quest diagnostic, USA)

10. 10
EPIC-Norfolk all cause mortality relative risk
AIC 5-5.4% 5.5-5.9% 6-6.4% 6.5-6.9%>6.9%
Men RR 1.25 1.57 1.8 3.49 3.38
Death
Women RR 1.02 1.28 1.61 1.71 6.91
Death

11. 11
HbA1c as a CV Risk Factor
“In men and women A1c concentrations predicted coronary heart,
cardiovascular disease, and total mortality… independent of
and only slightly attenuated after adjustment for known
risk factors.”
“an increase of A1c of 1 percentage point was associated with a
20-30% increase in event rates.”
• “…glycosylated hemoglobin can now be added to the list of
other clearly established indicators of cardiovascular risk..”
• “Thus, the presence or absence of diabetes is likely to become less
important than the level of glycosylated hemoglobin in
the assessment of CV risk…”